Determination of the Blowing Agent Distribution in Rigid Polyurethane Foam

The amount and distribution of blowing agent in rigid polyurethane foam were determined by several methods, which are described and compared. A method for solvent extraction with subsequent gas chromatographic analysis was developed and found to be advantageous for CFC-blown foam along with a combustion method (the Schoniger method), where the chloride ions formed were determined by titration. The solvent extraction method was successfully applied to blowing agents in CFC-free foams as well. Three methods involving heating and weight-loss determination were evaluated. They are easy to use, but corrections for thermal decomposition of the polymer are needed. About half of the total amount of CFC-11 in the investigated polyurethane foams from district heating pipes was found to be dissolved in the polymer matrix

Changing from petroleum to wood-based materials: critical review of how product sustainability characteristics can be assessed and compared

This paper reports on a literature survey on available approaches for the assessment of product sustainability, with a specific focus on assessing the replacement of non-renewable petroleum-based materials with renewable wood-based materials in absorbent hygiene products. The results are contrasted to needs in a specific material development project. A diverse number of methods exist that can help in assessing different product sustainability characteristics for parts of or whole product lifecycles. None of the assessment methods found include guidelines for how to make a case-specific interpretation of sustainability and there is a general lack of assessment parameters that can describe considerations in the comparison between the use of wood or petroleum as main raw material. One reason for this is lack of knowledge and/or consensus on how to describe and assess impacts of land and water use, e.g. on ecosystem services, different types of resource depletion and social impacts

Environmental performance of new wastewater and sludge treatment routes compared to conventional approaches

The value of life cycle assessments depends on their completeness and on how well the assessment answers the question asked. In the EU project ROUTES several case studies have been performed in order to evaluate innovative wastewater and sludge treatment scenarios against baseline scenarios, in order to understand whether the new ones perform better or worse from an environmental systems perspective and identify the hot spots in the studied systems from where the main environmental pressure originates. The performed LCA study assesses five impact categories, Global Warming Potential, Acidification Potential, Eutrophication Potential, Ozone Depletion Potential and Photochemical Ozone Creation Potential. This article discusses the relevance of the obtained results and identifies further assessments needed in order to provide a solid result. The study shows that, at present, although a limited number of impact categories are assessed, the studied energy-demanding technologies, like sequential batch biofilm granular reactor and membrane reactor, have a worse overall environmental performance compared to baseline scenarios, and points out electrical efficiency as the main area to put focus on to decrease the overall environmental impact. It also shows that the technologies aimed at sludge quality improvement exhibit a promising environmental performance, but further assessment, including LCA method development, is needed as the studied impact categories do not model the studied system in a thorough way when it comes to comparing agricultural application of sludge and other disposal options

Life Cycle Assessment of Cellulose Nanofibrils Production by Mechanical Treatment and Two Different Pretreatment Processes

Nanocellulose is a bionanomaterial with many promising applications, but high energy use in production has been described as a potential obstacle for future use. In fact, life cycle assessment studies have indicated high life cycle energy use for nanocellulose. In this study, we assess the cradle-to-gate environmental impacts of three production routes for a particular type of nanocellulose called cellulose nanofibrils (CNF) made from wood pulp. The three production routes are (1) the enzymatic production route, which includes an enzymatic pretreatment, (2) the carboxymethylation route, which includes a carboxymethylation pretreatment, and (3) one route without pretreatment, here called the no pretreatment route. The results show that CNF produced via the carboxymethylation route clearly has the highest environmental impacts due to large use of solvents made from crude oil. The enzymatic and no pretreatment routes both have lower environmental impacts, of similar magnitude. A sensitivity analysis showed that the no pretreatment route was sensitive to the electricity mix, and the carboxymethylation route to solvent recovery. When comparing the results to those of other carbon nanomaterials, it was shown that in particular CNF produced via the enzymatic and no pretreatment routes had comparatively low environmental impacts

Methodological issues in LCA of wastewater treatment combined with PHA biopolymer production

Production of polyhydroxyalkanoates (PHAs) by mixed microbial cultures utilising the organic content of wastewaters is one of the technologies studied in the EU project ROUTES. When comparing the life-cycle environmental impacts of simultaneous wastewater treatment and production of PHA-rich biomass to traditional wastewater and solids treatment, the handling of this multi-functionality is critical for the results. Only one LCA of such a system has been found in the literature. The current paper identifies substitution and allocation based on chemical oxygen demand removal as two possible options to account for the multi-functionality of the system. Examples based on literature data were used to show that for global warming potential, the choice of allocation method can substantially affect the results

Including Pathogen Risk in Life Cycle Assessment of Wastewater Management. 1. Estimating the Burden of Disease Associated with Pathogens

The environmental performance of wastewater and sewage sludge management is commonly assessed using life cycle assessment (LCA), whereas pathogen risk is evaluated with quantitative microbial risk assessment (QMRA). This study explored the application of QMRA methodology with intent to include pathogen risk in LCA and facilitate a comparison with other potential impacts on human health considered in LCA. Pathogen risk was estimated for a model wastewater treatment system (WWTS) located in an industrialized country and consisting of primary, secondary, and tertiary wastewater treatment, anaerobic sludge digestion, and land application of sewage sludge. The estimation was based on eight previous QMRA studies as well as parameter values taken from the literature. A total pathogen risk (expressed as burden of disease) on the order of 0.2–9 disability-adjusted life years (DALY) per year of operation was estimated for the model WWTS serving 28 600 persons and for the pathogens and exposure pathways included in this study. The comparison of pathogen risk with other potential impacts on human health considered in LCA is detailed in part 2 of this article series

Developing change agency for sustainable development : experiences from a new chemical engineering course

The chemical engineering programme at Chalmers University of Technology in Göteborg, Sweden, has had compulsory courses on environmental science, environmental engineering and sustainable development (SD) at bachelor level for many years. This paper reports on curriculum development projects performed in 2013 and 2014 aimed at improving the quality of the program curriculum with regard to the compulsory content on ‘environment and SD’ and on experiences of planning a new course that was developed as a result of these projects: Perspectives on chemical engineering. The curriculum development projects contrasted the existing curriculum to syllabi from upper secondary school, to needs expressed by industry, alumni and engineering students, and to state-of-the-art engineering education for SD, and ended up in, among other things, ideas to be implemented in a new course in the first year. The new course focuses on introducing chemical engineering and the professional role of the chemical engineer, and developing change agency for SD. The new course was given for the first time in late spring 2015. In the course, the students are doing a smaller individual change project in which they change something in their daily life for a week and assess the impact and reflect on the challenges in making the change. They also do a larger group project in which they make a sustainability assessment of a considered sustainability-motivated change in chemical industry, including reflecting on the challenges in achieving change. Industry representatives help to guide the students in the project. The course also introduces basic concepts and tools like life cycle perspective, mass balances, biorefinery and industrial symbiosis. Special care is put into attempting to constructively align teaching and learning activities and assessment to the overall goal of developing students’ change agency for SD. The paper reports on this endeavour. The presentation at the conference also reports on the actual experiences from giving the course for the first time, in particular in relation to change agency for SD.Non UBCUnreviewedFacultyOthe

Assessing "Wicked Sustainability Problem" - Literacy in Engineering Education

Environmental and sustainability problems are not purely technical problems. Many of the most pressing issues, such as climate change, resource scarcity, and pollution, require holistic approaches that go beyond technical systems analysis and optimization. Such problems have been called wicked sustainability problems (WSPs) because they are highly complex, contested, and lack definite solutions1,2. Engineering education has the potential to play an important role in preparing students to contribute to deal with problems such as WSP3,4. To be able to contribute in this way, students need to develop an ability to holistically and integratively understand and address WSPs while considering the normative context of sustainable development (here called WSP literacy). However, common practice in engineering education more commonly prepares students to address well-structured and tame rather than wicked problems5,6 . One reason may be that working together to develop complex competencies such as WSP literacy is challenging for students as well as educators. Wiek, Withycombe, and Redman suggest that formulating and operationalizing intended learning outcomes (ILOs) for complex competencies can facilitate this difficult process and thus improve engineering education practice4. In this paper, we provide a preliminary matrix of 22 concrete ILOs for WSP literacy, as well as two different approaches to assessing (some of) them in engineering education. We expect that engineering educators will find these ILOs and assessment strategies valuable for adopting a constructive alignment approach for WSP literacy in their teaching

Assessing "Wicked Sustainability Problem" - Literacy in Engineering Education

Environmental and sustainability problems are not purely technical problems. Many of the most pressing issues, such as climate change, resource scarcity, and pollution, require holistic approaches that go beyond technical systems analysis and optimization. Such problems have been called wicked sustainability problems (WSPs) because they are highly complex, contested, and lack definite solutions1,2. Engineering education has the potential to play an important role in preparing students to contribute to deal with problems such as WSP3,4. To be able to contribute in this way, students need to develop an ability to holistically and integratively understand and address WSPs while considering the normative context of sustainable development (here called WSP literacy). However, common practice in engineering education more commonly prepares students to address well-structured and tame rather than wicked problems5,6 . One reason may be that working together to develop complex competencies such as WSP literacy is challenging for students as well as educators. Wiek, Withycombe, and Redman suggest that formulating and operationalizing intended learning outcomes (ILOs) for complex competencies can facilitate this difficult process and thus improve engineering education practice4. In this paper, we provide a preliminary matrix of 22 concrete ILOs for WSP literacy, as well as two different approaches to assessing (some of) them in engineering education. We expect that engineering educators will find these ILOs and assessment strategies valuable for adopting a constructive alignment approach for WSP literacy in their teaching